1. Field of the Invention
This invention relates to a method for reproducing electronically stored data and an apparatus or reproduction device for performing the method.
2. Description of the Prior Art
Devices of the aforementioned type are known from various applications in data processing technology. For example it is conventional in a laser scanner to utilize pointwise scanning, especially with a beam of light or electrons, a scanning electron microscope, or an electron beam tube. The image is recorded linewise with a scanning head and may be broken up into three color components. It is conducted in the form of electrical signals to the color computer and processed thereby. The output signals of the color computer control the laser, possibly through a modulating unit, with the light of the laser exposing the film with the aid of the write head.
In addition, it is known from digital image conversion, recognition and processing to perform scanning to generate bit patterns associated with the individual points in a grid and containing information on corresponding points of the pattern in digital form. The bit patterns can be processed further in a digital computer, such as for recognition and recoding of writing (characters, alphabets) that are either encoded in turn or are in cleartext. Scanning must be performed at intervals short enough that the reaction to changes in state is sufficiently rapid.
In a known laser scanner, the laser pulses are conventionally deflected by a multisurface facetted mirror, rotating at high speed. The laser beam is deflected many times and focused in a special correcting lens arrangement. Because of the long path lengths and lens errors in the correcting optics that cannot be completely avoided, distortions occur in the imaging of the reflected pulses. In addition, with a slight skew of the rotating mirror, scattering effects can occur that lead to distortion of the imaged pulses, as well as errors that occur in manufacture of mass-produced products and in the transition to simpler designs with a compact form.
In the optical device itself, a lens alignment error is frequently encountered that is responsible for an angle error that results in distortion and unclear images.
The objective of the present invention is to avoid disadvantages and sources of error and to provide a device for reproducing electronically stored data in which the use of an optical correcting device can be eliminated and imaging accuracy can be improved at the same time. The reproducing device is intended to have a design that is as compact as possible, consists of technically simple components, and nevertheless provides high-grade transmission and imaging quality.